Automatic lens grinding and polishing machine



. March 1958 E. M. KATZENBERG 2,826,874

AUTOMATIC LENS GRINDING AND POLISHING MACHINE Filed 001;. 14, 1955 INVENTOR. EDGAR M. KATZENBERG BY v T TORNEYS AUTOMATIC LENS GRINDING AND POLISHING MACHINE Edgar M. Katzenberg, Columbus, Ohio-,assignor'to Robg lslon-Houchiu, Inc., Columbus, Ohio, a corporation of Application- October 14, 1955, Serial No. 540,470

2' Claims. 31. 51-460 My invention relates to an automatic lens grinding and polishing machine. It has to do, more particularly, with a machine for grinding and polishing lenses in which means is provided for timing the period of grinding or polishing and in which means is also provided for timing the automate feeding of the abrasive relative to the grinding-or polishing period.

With lens polishing machines of the type now commonly in use, it is customary to provide means for automatically feeding the liquid suspension of rouge during the polishing operation. lens polishing lap and the lens blank during the polishing operation, the lap and blank being moved relatively during this operation. With most jobs, it is customary to interrupt the feed of the liquid rouge to the lens blank and lap a short interval before the polishing is completed. In other words, the last step in the polishing operation, in most cases, is what is known as dry polishing. This period of dry polishing will vary with the type of lens blank being produced and with machines now commonly in use depends Wholly upon the skill of the operator.

It is the object of this invention to provide a lens grinding or polishing machine in which the machine is automatically controlled so as to provide a preselected period of grinding or polishing and to provide a preselected period during the final stages of the grinding or polishing operation during which the supply of abrasive to the lens blank and lap is interrupted.

In the accompanying drawing I have illustrated a machine in which my invention is embodied but it is to be understood that this machine may take other forms. In this drawing:

Figure 1 is an isometric view, partly broken away, illustrating a lens polishing machine to which my invention is applied.

Figure 2 is a diagrammatic view of the circuit of the control system which I use on the machine.

In Figure 1, I have illustrated a machine of a type in which my invention may be embodied. This machine may be of the general construction disclosed in the patent to Lowell Houchin, No. 2,105,691, which issued January 18, 1938. This machine includes the lap supporting tables 10 (only one of which is shown), the lens blank holding units 11, which support the lens blanks in contact with the laps on the respective tables 10, and means within the casing 12 (not shown) for producing the desired movement of the tables 10 in order to produce the desired movement between the lens blanks supported by the means 11 and the laps supported by the tables 10. This latter means is driven by the main motor 14 which is within the casing 12, as indicated in Figure 1.

Enclosing the lap tables 10 is a pan 15 which serves as a sump for collecting the liquid rouge applied to the associated laps and lens blanks. A pump 20 is connected to the bottom of the pan or sump 15 and its outlet line leads to a manifold formed on a housing 21 which is disposed on the top of the casing 12 and upon which This rouge is fed between the nited States Patent the lens holding units are mounted. The pump 20 is driven by a suitable driving motor 22 on the machine. The manifold of the housing 21 is connected to each of the lap supporting tables 10 by suitable connections 23. The rouge supplying system, as described in said application, supplies the rouge automatically up through the lens blank supporting tables 10 between the laps and the lens blanks supported by the units 11.

The automatic control system which I provide for this machine is adapted to drive the main motor 14' and the pump motor 22 for preselected periods. Furthermore, this control system will interrupt operation of the pump motor 22 a short period before the operation of the main motor 14 is interrupted. This control system includes a number of units which are disposed in the housing 21 which is mounted on top of the casing 12. The system includes time delay relays T1 and T2 which are selected by a selector switch 24 on the top of the housing 21, a relay R, and a single pole double throw timer motor M which is set by means of a knob 25 cooperating with a dial on the top of the housing 21.

In the operation of this machine, the operator starts the machine by setting the knob 25 of the main timer M for the desired polishing period. He also operates the knob 24 of the selector switch of the secondary timing means to select either a short period or long period of dry polishing or no period at all. This throws the timer contact into its off-normal position which energizes the following: the timer motor of the timer M; the pump motor 22; the heater, on either time delay relay T1, T2, or no time delay relay at all depending on the setting of selector switch 24; and the main machine motor 14. The polishing machine and the pump for the rouge are now both operating. After a short interval has passed and the energization time of the selected time delay relay has been reached, either contact T1 or T2 of the time delay relay will close, unless switch S is on the OE position. This energizes relay R, switching contact r thereof to the oif-normal position. The machine motor 14 continues to run through the off-normal contact, and the operator does not realize that this switching has occurred since there is no external efiect. Next, the time set on the manual set timer M is reached, and the timer contact opens. This breaks the circuit to the timer motor, pump motor 22, and time delay relay heater. The pump motor 22 and pump 20 shut off, but the machine motor 14 continues to run, to continue the polishing operation, until the time delay relay heater cools sufiiciently to allow contact T1 or T2 to reopen and deenergize relay R, thus breaking the circuit to the machine motor 14 and interrupting the polishing operation. If the selector switch knob 24 is on the off position, relay R will never energize and the machine motor 14 will shut off at the same time as the pump motor 22 so that there will be no dry polishing period.

It will be apparent from the above description that I have provided a lens polishing machine in which the polishing period can be selected and the machine will automatically stop when the period is completed. Furthermore, with this machine, the period during which the automatic rouge feeder operates relative to the period of polishing can be selected so as to provide for dry polishing or not as desired. Also, the dry polishing period can be selected to be of long or short duration.

Various other advantages will be apparent.

Having thus described my invention, what I claim is:

1. A lens grinding and polishing machine comprising a lap supporter and a lens blank holder for positioning a lap and lens blank in contact for grinding and polishing the blank, means for producing relative movement between the lap supporter and the lens blank holder to move the contacting lap and lens blank relatively for i the grinding and polishing operations, an abrasive-supplying system for supplying abrasive in the form of liquid rouge between the contacting lap and lens blank, said abrasive-supplying system including a pump, a first electric motor for driving said means for producing relative movement of the lap supporter and the lens blank holder, a second electric motor for driving said pump, an electric control system, said electric control system comprising main adjustable timing means connected in a circuit for controlling both of said motors, and secondary adjustable timing means connected in the circuit to control said pump driving motor to disconnect it from said circuit at a preselected instant, said main timing means comprising a timing motor and said secondary timing means comprising a time-delay relay including contacts for controlling said first electric motor which drives said abrading means, said time-delay relay including a heater 4 which is controlled by said timing motor and which controls said relay contacts.

2. The combination of claim 1 in which two time-delay relays are provided for different time-delay periods, and a selector switch for selecting either or neither of said time-delays relays.

References Cited in the file of this patent UNITED STATES PATENTS 2,105,691 Houchin Jan. 18, 1938 2,251,161 Packer July 29, 1941 2,541,283 Praeg Feb. 13, 1951 2,576,787 Hall Nov. 27, 1951 2,620,602 Schenk Dec. 9, 1952 2,639,557 McMullen May 26, 1953 2,673,423 Hoyet Mar. 30, 1954 2,677,219 Burt H May 4, 1954 

